1. Field of the Invention
The present invention relates to a photodiode array and a method of making the same.
2. Related Background Art
Photodiode arrays for CT (computed tomography) have been required to have a larger area. For eliminating insensible regions from a photodiode array, three-dimensional packaging is necessary, in which a signal processing unit is disposed on the opposite side (rear side) of the light incident surface. To this aim, it is necessary for an electrode formed on the incident side (front side) by using a through hole wiring to be drawn to the opposite side (rear side) of the incident surface.
Semiconductor devices using such a through hole wiring are disclosed, for example, in the following Patent Documents 1 and 2. In the semiconductor device disclosed in the Patent Document 1, a substrate is etched by wet etching with an alkali solution in order to form a through hole, whereby the revealed plane of substrate is at an angle of 54.7° with respect to the substrate surface.
Patent Document 1: Japanese Patent Application Laid-Open No. HEI 5-29483
Patent Document 2: Japanese Patent Application Laid-Open No. HEI 6-177201